Recently, copying machines are at hand in every office, and necessary documents can be readily copied. Resultantly, offices are full of large volumes of copies, which causes troubles, In order to solve the troubles. efficient storage of the copies is sought. Furthermore, it has come even to the paperless system being proposed so as to expel papers out of offices. On the other hand, volumes of information are on steady increase. Access to large volumes of information is necessary for business.
Thus it is contradictorily required that large volumes of information are necessary for business, while increases of their documents must be avoided as much as possible for office environments.
One of the means for storing documents in optical disks is the electronic file system. The storage of documents in optical disks by the electronic file system can contribute to space savings.
But the conventional electronic file system requires a considerably cumbersome electronic file unit, and requires complicated registration/retrieval keys for storing documents, and full time operators. When a document stored in an optical disk is required, an input is made by keys in accordance with a complicated registration/retrieval key system to read the document, which needs full time operator' assistance.